U.S. patent number 8,881,374 [Application Number 11/776,339] was granted by the patent office on 2014-11-11 for method of manufacturing for a disk drive head suspension for a fold over limiter.
This patent grant is currently assigned to Hutchinson Technology Incorporated. The grantee listed for this patent is Jacob D. Bjorstrom, Reid C. Danielson, Eric O. Naatz, John A. Rickeman. Invention is credited to Jacob D. Bjorstrom, Reid C. Danielson, Eric O. Naatz, John A. Rickeman.
United States Patent |
8,881,374 |
Bjorstrom , et al. |
November 11, 2014 |
Method of manufacturing for a disk drive head suspension for a fold
over limiter
Abstract
A method for manufacturing a disk drive head suspension
including a load beam, a flexure and a limiter for restricting the
range of motion of the flexure with respect to the load beam. The
load beam includes an aperture and an engaged portion adjacent to
the aperture. The flexure, in an unformed state, includes a slider
mounting region and a generally planar engagement structure
extending from the slider mounting region. The engagement structure
includes a tab portion extending from the slider mounting region
and a hook portion extending from the tab portion. During a first
forming operation the hook portion is bent around a tooling die to
a ninety degree angle with respect to the tab portion. The flexure
is then welded to the load beam with the hook portion extending
into the aperture. During a second forming operation the tab
portion is bent around a tooling die to a ninety degree angle with
respect to the slider mounting region. The second forming operation
causes the hook to extend over the engaged portion of the load
beam. The first and second forming operations can be performed with
tooling moving only in a z-direction.
Inventors: |
Bjorstrom; Jacob D.
(Hutchinson, MN), Danielson; Reid C. (Cokato, MN), Naatz;
Eric O. (Litchfield, MN), Rickeman; John A. (Hutchinson,
MN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Bjorstrom; Jacob D.
Danielson; Reid C.
Naatz; Eric O.
Rickeman; John A. |
Hutchinson
Cokato
Litchfield
Hutchinson |
MN
MN
MN
MN |
US
US
US
US |
|
|
Assignee: |
Hutchinson Technology
Incorporated (Hutchinson, MN)
|
Family
ID: |
51845626 |
Appl.
No.: |
11/776,339 |
Filed: |
July 11, 2007 |
Current U.S.
Class: |
29/603.03;
360/245.7; 29/603.04; 360/245.4 |
Current CPC
Class: |
G11B
5/4833 (20130101); Y10T 29/49027 (20150115); Y10T
29/49025 (20150115) |
Current International
Class: |
G11B
5/48 (20060101) |
Field of
Search: |
;29/603.03,603.04,432,437,DIG.3,521 ;360/245,245.5,245.7,245.4
;72/379.2 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Tugbang; A. Dexter
Attorney, Agent or Firm: Faegre Baker Daniels LLP
Claims
What is claimed is:
1. A method for manufacturing a disk drive head suspension having
first and second components and a limiter structure for limiting
motion between the first and second components, including:
providing a first component having an engaged structure including
an open region and an engaged portion adjacent to the open region;
providing a second component having an unformed engaging structure
including a hook portion and a tab portion extending from a
motion-limited structure, wherein the hook portion is distal to the
tab portion and the tab portion is between the hook portion and the
motion-limited structure, and wherein the unformed engaging
structure is coplanar with a portion of the motion-limited
structure from which the unformed engaging structure extends;
forming the hook portion with respect to the tab portion thereby
changing the unformed engaging structure to an engaging structure;
positioning the first component with respect to the second
component after forming the hook portion of the engaging structure
on the second component, including extending the hook portion of
the engaging structure into the open region of the engaged
structure; and forming the tab portion of the engaging structure
with respect to the motion-limited structure after the first
component is positioned with respect to the second component,
wherein forming the tab portion after the first component is
positioned with respect to the second component causes the tab
portion to extend into the open region and causes the hook portion
to extend over the engaged portion of the first component.
2. The method of claim 1 wherein forming the hook portion includes
bending the hook portion with respect to the tab portion about a
tooling die.
3. The method of claim 2 wherein bending the hook portion includes
engaging the hook portion with tooling and moving the tooling in a
z-direction with respect to the tab portion.
4. The method of claim 1 wherein positioning the first component
with respect to the second component includes moving the first and
second components in a z-direction with respect to one another.
5. The method of claim 1 wherein forming the tab portion includes
bending the tab portion with respect to the motion-limited
structure about a tooling die.
6. The method of claim 5 wherein bending the tab portion includes
engaging the tab portion with tooling and moving the tooling in a
z-direction with respect to the motion-limited structure.
7. The method of claim 6 wherein moving the tooling includes moving
the tooling into the open region of the first component.
8. The method of claim 5 wherein bending the tab portion includes
causing the hook to move without interference from the tooling die.
Description
FIELD OF THE INVENTION
The invention is a limiter for a disk drive head suspension, and a
method for manufacturing the limiter.
BACKGROUND OF THE INVENTION
Limiters for constraining the range of motion of one portion or
component of a disk drive head suspension with respect to another
portion or component are well know. For example, limiters are often
used to limit the motion of the slider mounting region of a flexure
with respect to a load beam to which the flexure is attached.
Limiters of these types and methods for manufacturing the limiters
are disclosed, for example, in the Brooks, Jr. et al. U.S. Pat. No.
5,892,637.
Disk drive head suspension limiters can generally be classified
into one of two categories. The first category is limiters that are
formed after the two components have been assembled (e.g., welded)
to one another. The limiter shown in the Davis et al. U.S. Pat. No.
6,172,853 is an example of a limiter of this first category.
Limiters formed after component assembly are often easy to
manufacture, and have relatively tight tolerance limiter gaps (the
amount of space between the engaging and engaged portions of the
structure). Unfortunately, the limiters often have relatively low
limiter engagement (the amount of overlap between the engaging and
engaged portions). Limiters with low engagement are prone to
unhooking.
The second category is limiters that are formed before the two
components are assembled. The limiter shown in the Prentice et al.
U.S. Pat. No. 5,333,085 is an example of a limiter of this second
category. The assembly of these limiters requires the merger of the
engaging and engaged portions or components. The merge process
often involves motion along more than one axis, something that can
complicate the suspension manufacturing process. Although merged
limiters often have higher limiter engagement making them less
susceptible to unhooking, the merge process often makes it more
difficult to control the limiter gap.
There remains a continuing need for improved limiter structures and
methods of manufacture and assembly. A limiter that can be formed
after assembly, and provide both high engagement and tight limiter
gap specifications would be particularly desirable.
SUMMARY OF THE INVENTION
The invention is a limiter having both high limiter engagement and
tight limiter gap specifications that can be formed and assembled
without merge operations requiring motion in more than one
direction. A suspension having a limiter in accordance with one
embodiment of the invention includes a first suspension component
having an engaged structure and a second component attached to the
first component and having an engaging structure. The engaged
structure of the first component comprises an open region and an
engaged portion adjacent to the open region. The engaging structure
of the second component comprises a motion-limited region, a tab
and a hook. The tab has a width extending from the motion-limited
region into the open region of the first suspension component. The
hook has a width that is less than the width of the tab and extends
from the tab over the engaged portion of the first suspension
component.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric illustration of the distal end of a
suspension assembly including a fold over limiter in accordance
with one embodiment of the invention.
FIG. 2 is a detailed isometric illustration of the limiter shown in
FIG. 1.
FIGS. 3A-3D are isometric illustrations showing a sequence of steps
in accordance with another embodiment of the invention for
manufacturing the limiter shown in FIG. 1.
FIGS. 4 and 5 are isometric illustrations of the distal end of a
suspension assembly including a fold over limiter in accordance
with another embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The distal portion of a suspension assembly 8 including a fold over
limiter 10 in accordance with one embodiment of the invention is
illustrated in FIGS. 1 and 2. As shown, the suspension assembly 8
includes a load beam 12 and an integrated lead or wireless flexure
14 attached to the load beam. With the exception of the limiter 10,
load beam 12 and flexure 14 can be of conventional design and
manufacture. In the illustrated embodiment, the flexure 14 includes
a base region 16 attached to the load beam 12 and a gimbal region
18. The gimbal region 18 includes a pair of spaced-apart spring
arms 20 extending from the base region 16, a cross bar 22 extending
between the ends of the spring arms, and a tongue or slider
mounting region 24 extending from the cross bar into a gap between
the spring arms. Electrical traces 26 extend from the base region
16 of the flexure, over the gimbal region 18, and terminate at bond
pads (not visible) on the slider mounting region 24 near the cross
bar 22. The distal end of the load beam 12 includes a load point
dimple 28 that engages the slider mounting region 24 of the flexure
14. Portions of the load beam 12 at locations further away from the
gimbal region 18 than those shown in FIGS. 1 and 2 often, but need
not, include stiffening rails on their edges.
Fold over limiter 10 includes an L-shaped engaging structure 30
extending from the proximal end of the slider mounting region 24
and an engagement structure 32 on the load beam 12. The engaging
structure 30 cooperates with the engagement structure 32 to limit
the range of movement of the slider mounting region 24 with respect
to the load beam 12. In the illustrated embodiment, the engagement
structure 32 includes an aperture 34 in the load beam 12 and an
engaged portion 36 of the load beam adjacent to the aperture. The
engaged portion 36 is a projection extending into the aperture 34
in the illustrated embodiment, although other embodiments (not
shown) do not include such a projection. The engaging structure 30
includes a tab 38 extending from the slider mounting region 24 into
the aperture 34, and a hook 40 extending from the tab over the
engaged portion 36. In the illustrated embodiment, the tab 38 is
generally centrally located on the proximal end of the slider
mounting region is formed by a pair of spaced legs 42 and a bridge
44 extending between the legs. As described below, the legs 42
function as forming support regions during the manufacture of the
limiter 10. The hook 40 extends from a generally central location
on the bridge 44. As shown, the tab 38 and hook 40 are generally
planar members in the illustrated embodiment. The width of the hook
40 is less than the width of the tab 38. The hook 40 is thereby
transversely offset from at least portions of the tab 38
intersecting the slider mounting region 24. As shown, the hook 40
is sufficiently long to overlap the engaged portion 36 by a
significant distance, thereby providing the limiter 10 with high
engagement.
In other embodiments (not shown), the engaging structure can be on
the load beam or another component extending over the gimbal region
(e.g. a stiffener member), and the engagement structure on the
slider mounting region. In still other embodiments, the engaging
structure can be located at other locations on the slider mounting
region or the gimbal region. The engagement structure can be
located at other portions of the suspension assembly, and can be on
the edge of the structure and include an opening rather than an
aperture. The engaging structure can also take other forms (not
shown). The aperture 34 can also take other forms while still
providing clearance for the forming operation described below. In
the illustrated embodiment of the invention the engaging structure
30 extends in a direction that is generally parallel to a
longitudinal axis of the suspension assembly 8. However, in other
embodiments (not shown) the engaging structure can extend in other
directions (e.g., in a direction parallel to a transverse direction
of the suspension assembly).
A method for manufacturing a suspension assembly 8 including a fold
over limiter 10 can be described with reference to FIGS. 3A-3D.
FIG. 3A is an illustration of a distal end of a flexure 14' having
an unformed engaging structure 30', including the unformed tab 38'
and unformed hook 40', on the proximal end of the slider mounting
region 24. Flexure 14' can be formed using conventional additive
and/or subtractive photolithographic, deposition and etching
processes. In the embodiment shown in FIG. 3A, the unformed
engaging structure 30' is integral and coplanar with and formed
from the same material as the slider mounting region 24.
FIG. 3B shows a first forming process that is performed on the
engaging structure 30'. As shown, tooling such as a first forming
die 60 is positioned on the flexure 14' with a forming edge of the
die located on the bend path at which it is desired to bend the
hook 40' with respect to the tab 38'. In one embodiment, the
forming die 60 is positioned on at least the tab 38' with the hook
40' extending beyond the forming edge of the die. Tooling such as a
wiper (not shown) is then engaged with the hook 40' and driven with
respect to the die 60 to form the hook with respect to the tab 38'.
In one embodiment this forming operation is performed by driving
the wiper in a direction 62 (known as the Z-direction) that is
generally perpendicular to the planar surface of the tab 38'. The
hook 40' is formed to an angle of approximately ninety degrees with
respect to the tab 38' in one embodiment, although the hook can be
formed to other angles with respect to the tab in other embodiments
(not shown). The forming die 60 is withdrawn from the flexure 14'
after the first forming operation.
After the first forming operation the load beam 12 is positioned at
the desired location with respect to the flexure 14' as shown in
FIG. 3C. The formed hook 40' will extend into the aperture 34
following this component placement operation. Conventional
processes such as welding (not shown) can then be used to attach
the partially formed flexure 14' to the load beam 12. Conventional
component manipulation processes can be used to position the
flexure 14' and load beam 12 with respect to one another. Because
the effective footprint of the formed hook 40' is relatively small
with respect to the aperture 34, only motion in the z-direction is
necessary to move the hook into the aperture.
FIG. 3D shows a second forming process that is performed on the
engaging structure 30'. Tooling such as a second tooling die 64 is
positioned on the flexure 14' and/or load beam 12 with a forming
edge of the die located on the bend path at which it is desired to
bend the tab 38' with respect to the slider mounting region 24. In
particular, the die 64 has a forming edge that is located along the
bend path at locations that are transversely spaced from the
intersection of the tab 38' and hook 40'. In the illustrated
embodiment this is achieved by a die 64 having a pair of
spaced-apart arms 66 that is positioned on the flexure 14' with the
forming edges at the intersections of the tab legs 42' and the
slider mounting region 24. The arms 66 of tooling die 64 are spaced
apart by a distance that allows the hook 40' to move without
interference from the tooling die during the second forming
operation. Similarly the space between the arms 66 of the tooling
die 64 is long enough to allow the length of the hook 40' to move
without interference from the tooling die during the forming
operation.
Tooling such as a wiper (not shown) is engaged with the tab 38' and
driven with respect to the tooling die 64 to form the tab with
respect to the slider mounting region 24. In one embodiment this
forming operation is performed by driving the wiper in a direction
68 (the Z-direction) that is generally perpendicular to the planar
surface of the slider mounting region 24. The tab 38' is formed to
an angle of approximately ninety degrees with respect to the slider
mounting region 24 in one embodiment, although the tab can be
formed to other angles with respect to the slider mounting region
in other embodiments (not shown). During this forming operation the
hook 40' moves through the space between the arms 66 of the die 64
and over the engaged portion 36 of the load beam 12. In one
embodiment of the invention, the second forming operation is
performed to position the hook 40' in a generally parallel
orientation with respect to the engaged portion 36 and/or the
slider mounting region 24. In other embodiments (not shown) the
hook 40' can be non-parallel to the slider mounting region. In
general, the aperture 34 must be large enough to accommodate any
portions of the wipers that extend into the aperture during the
second forming operation. The second forming operation can be
performed with wiper motion only in the z-direction. After the
second forming operation the die 64 is withdrawn.
Other methods can also be used to manufacture suspension assemblies
8 including fold over limiter 10. For example, the distal end of a
flexure having an unformed engaging structure, including an
unformed tab and an unformed hook on the proximal end of a mounting
region (e.g., a flexure such as 14' shown in FIG. 3A) can be welded
or otherwise attached to a load beam having an engaging structure
(e.g., the load beam 12 shown in FIG. 3B). After this attachment
step, the first and second forming steps described above can be
performed on the engaging structure (i.e., the tab 38 and the hook
40 can be formed after the flexure 14 is assembled onto the load
beam 12).
FIGS. 4 and 5 illustrate the distal portion of a suspension
assembly 108 including a fold over limiter 110 in accordance with
another embodiment of the invention. As shown, the suspension
assembly 108 includes a load beam 112 and a flexure 114 attached to
the load beam. With the exception of the limiter 110, load beam 112
and flexure 114 can be of conventional design and manufacture. In
the illustrated embodiment, the flexure 114 includes a base region
116 attached to the load beam 112 and a gimbal region 118. The
gimbal region 118 includes a pair of spaced-apart spring arms 120
extending from the base region 116, a cross bar 122 extending
between the ends of the spring arms, and a tongue or slider
mounting region 124 extending from the cross bar into a gap between
the spring arms. The distal end of the load beam 112 includes a
head lift tab 127. Portions of the load beam 112 at locations
further away from the gimbal region 118 than those shown in FIGS. 4
and 5 often, but need not, include stiffening rails on their
edges.
Fold over limiter 110 includes a generally L-shaped engaging
structure 130 (as seen from its edge) extending from the proximal
end of the slider mounting region 124 and an engagement structure
132 on the load beam 112. The engaging structure 130 cooperates
with the engagement structure 132 to limit the range of movement of
the slider mounting region 124 with respect to the load beam 112.
In the illustrated embodiment, the engagement structure 132
includes an aperture 134 in the load beam 112 and an engaged
portion 136 of the load beam adjacent to the aperture. The engaged
portion 136 is a projection extending into one side of the aperture
134 in the illustrated embodiment, although other embodiments (not
shown) do not include such a projection. The engaging structure 130
includes a tab 138 extending from the slider mounting region 124
into the aperture 134, and a hook 140 extending from the tab over
the engaged portion 136. In the illustrated embodiment, the tab 138
is generally centrally located on the proximal end of the slider
mounting region 124 and extends generally transversely across the
end of the slider mounting region. The tab 138 functions as a
forming support region during the manufacture of the limiter 110.
The hook 40 extends from the side of the tab 138 adjacent to the
engaged portion 136 of the load beam 112. As shown, the tab 138 and
hook 140 are generally planar members in the illustrated
embodiment. The width of the hook 140 is less than the width of the
tab 138. The hook 140 is thereby transversely offset from at least
portions of the tab 138 intersecting the slider mounting region
124. As shown, the hook 140 is sufficiently long to overlap the
engaged portion 136 by a significant distance, thereby providing
the limiter 110 with high engagement. As perhaps best shown in FIG.
4, in the illustrated embodiment the tab 138 is connected to the
slider mounting region 124 only at a location that is transversely
offset from the location at which the hook 140 is connected to the
tab. Suspension assembly 108 and fold over limiter 110 can be
manufactured in a manner similar to that of suspension assembly 8
and limiter 10 described above.
The invention offers a number of important advantages. The limiter
is capable of providing a high degree of engagement with a low gap
height. By way of example, the invention can be used to produce
limiters having 270 .mu.m engagement length and 10 .mu.m gap
heights. Other embodiments of the limiter can have greater or
lesser engagements and gap heights. These features can also be
efficiently achieved by merge-free processes that necessitate
motion only in the z-direction.
Although the invention has been described with reference to
preferred embodiments, those skilled in the art will recognize that
changes can be made in form and detail without departing from the
spirit and scope of the invention.
* * * * *